Recently, technical development as to the improvement in performance of smaller droplets, higher drive frequency and increased numbers of nozzles is continued in order to make the recording characteristics more advanced in an ink jet recording system. And image recording is performed by ejecting liquid from an ejection opening as small droplets which adhere to the recording medium typified by paper.
Here, a surface treatment is becoming more important to maintain ejecting performance by keeping ejecting opening surface as the same condition at any time.
Moreover, it is common to wipe off the ink which remained on the surface by e.g. rubber blades periodically to maintain the condition of the ejecting opening surface in an ink jet head. A liquid repellent material is demanded for easy wiping, and wiping durability.
Since the ink used for an ink jet head is not neutral in many cases, it is also required that the liquid repellent material should have durability against ink and have adhesion power to a nozzle.
Furthermore, since precise nozzle structure is required for a nozzle in order to obtain a high-quality image in recent years, it is also required that the liquid repellent material should have photo-sensitive characteristic of corresponding to patterning by photo-lithography.
This invention applies the hydrolyzable silane compound that has fluorine containing group to the liquid repellent processing on the surface of a nozzle.
The following official report is raised as a conventional example using the hydrolyzable silane compound that has a fluorine containing group.
Japanese patent Application Laid-Open No. H06-171094 and No. H06-210857 are indicating the method of performing the so-called silane coupling processing to the nozzle surface which formed the oxide particle layer beforehand using the hydrolyzable silane compound which has a fluorine containing group.
However, sufficient wiping durability is not acquired by the above-mentioned method. Furthermore, it is difficult to give the photo-sensitive characteristic to liquid repellent material by the above-mentioned system.
U.S. Pat. No. 5,910,372, EP B1 778869 and Japanese patent publication No. H10-505870 are indicating the possibility of the application to the coating and the ink jet nozzle which consists of a condensed composition which comprises a hydrolyzable silane compound having a fluorine containing group, and a silane compound having substitutes that react with the substrate. And, amino groups, carboxylic groups and so on are mentioned as the substitutes that react with the substrate.
In the above-mentioned composition, cross-linking of a liquid repellent layer means formation of siloxane network through the hydrolysis and condensation.
Generally cross-linked siloxane network affected by the ink that used in the ink jet recording system, especially when it is not a neutral aqueous solution. Siloxane network is re-hydrolyzed and liquid repellency decreases. Moreover above-mentioned composition does not refer to the photo-sensitive characteristic.
U.S. Pat. No. 6,283,578, EP B1 816094 are disclosing surface treatment for liquid repellent nature with silane compounds having a photo-radical polymerizable group. In this composition, cross-linking of a liquid repellent layer means formation of siloxane network and photo-radical polymerization. And photo-radical polymerization is corresponding photo-sensitive characteristic. Liquid repellency is derived from siloxane network itself.
Moreover, the above-mentioned specification is referring to the coating of a hydrolyzable silane compound having a fluorine containing group as the 2nd layer on the above-mentioned siloxane structure, when the higher liquid repellency is required.
However, in the above-mentioned two-layer composition, since there is no photo-sensitive characteristic in the hydrolyzable silane compound layer itself that has a fluorine containing group, the photo-sensitive characteristic cannot be given.
Jpn. J. Appl. Phys. Vol. 41 (2002) P. 3896-3901 is disclosing condensation products of specific aryl silane and a hydrolyzable silane compound having a fluorine containing group as a liquid repellent layer which shows excellent durability in alkaline ink. However, in this above-mentioned composition, addition of photo-sensitive characteristic is difficult.
Moreover, this applicant has proposed the method given in Japanese patent Application Laid-Open No. H04-10940 to No. H04-10942 as the high quality IJ recording method.
Furthermore, this applicant has proposed the method given in Japanese patent Application Laid-Open No. H06-286149 as the manufacturing method of the optimal IJ head for the above-mentioned IJ recording method given in Japanese patent Application Laid-Open No. H04-10940 to No. H04-10942.
The above-mentioned method uses photo-sensitive materials for a nozzle portion, and realizes precise nozzle structure with photolithography technology.
The liquid repellent material shown in the above-mentioned conventional example here was difficult to have the photo-sensitive characteristic, and application for the nozzle formation using photolithography technology was difficult.
On the other hand, this applicant has proposed the material of a publication to Japanese patent Application Laid-Open No. H11-322896, No. H11-335440, No. 2000-322896 as a liquid repellent material that have the photo-sensitive characteristic applicable to the above-mentioned Japanese patent Application Laid-Open No. H06-286149.
Although the above mentioned liquid repellent materials are excellent in respect of photo-sensitive characteristic, high liquid repellency, and adhesion force with the nozzle material etc., higher liquid repellency, durability (to maintain high liquid repellency) against the wiping and the ease of wiping are required, because they need to output a higher-quality image at high speed.
U.S. Pat. No. 5,644,014, EP B1 587667 and Japanese patent publication No. 3306442 are indicating the liquid repellent material using the hydrolyzable silane compound which has a fluorine containing group.
Although the above-mentioned material is indicating the photo curability using photo radical polymerization, it is not mentioned about formation of pattern using photo lithography technology or the application to an ink jet head.